midi note drags are music-based.

	- wysiwyg (during drag) when dragging more than one note across
	  a tempo change.

	- introduces a muscal equivalent of snap_delta (only used for
	  note drags atm)

	- split earliest note in selection into a separate function

	- MRV::copy_selection() returns the equivalent _primary note
  	  to avoid offset hell.

	- RV::snap_frame_to_frame returns a MusicFrame

	- prevent note drag moving before region start.

7 files changed, 134 insertions, 94 deletions

diff --git a/gtk2_ardour/automation_region_view.cc b/gtk2_ardour/automation_region_view.cc
index 8354e16b10..e3e41b4428 100644
--- a/gtk2_ardour/automation_region_view.cc
+++ b/gtk2_ardour/automation_region_view.cc
@@ -183,7 +183,7 @@ AutomationRegionView::add_automation_event (GdkEvent *, framepos_t when, double
 
 	/* snap frame */
 
-	when = snap_frame_to_frame (when - _region->start ()) + _region->start ();
+	when = snap_frame_to_frame (when - _region->start ()).frame + _region->start ();
 
 	/* map using line */
 
diff --git a/gtk2_ardour/editor_drag.cc b/gtk2_ardour/editor_drag.cc
index 7624546347..cf24ddbe9e 100644
--- a/gtk2_ardour/editor_drag.cc
+++ b/gtk2_ardour/editor_drag.cc
@@ -238,6 +238,7 @@ Drag::Drag (Editor* e, ArdourCanvas::Item* i, bool trackview_only)
 	, _grab_frame (0)
 	, _last_pointer_frame (0)
 	, _snap_delta (0)
+	, _snap_delta_music (0.0)
 	, _constraint_pressed (false)
 {
 
@@ -355,6 +356,15 @@ Drag::snap_delta (guint state) const
 
 	return 0;
 }
+double
+Drag::snap_delta_music (guint state) const
+{
+	if (ArdourKeyboard::indicates_snap_delta (state)) {
+		return _snap_delta_music;
+	}
+
+	return 0.0;
+}
 
 double
 Drag::current_pointer_x() const
@@ -373,11 +383,18 @@ Drag::current_pointer_y () const
 }
 
 void
-Drag::setup_snap_delta (framepos_t pos)
+Drag::setup_snap_delta (MusicFrame pos)
 {
-	MusicFrame snap (pos, 0);
+	TempoMap& map (_editor->session()->tempo_map());
+	MusicFrame snap (pos);
 	_editor->snap_to (snap, ARDOUR::RoundNearest, false, true);
-	_snap_delta = snap.frame - pos;
+	_snap_delta = snap.frame - pos.frame;
+
+	_snap_delta_music = 0.0;
+
+	if (_snap_delta != 0) {
+		_snap_delta_music = map.exact_qn_at_frame (snap.frame, snap.division) - map.exact_qn_at_frame (pos.frame, pos.division);
+	}
 }
 
 bool
@@ -618,7 +635,7 @@ void
 RegionMotionDrag::start_grab (GdkEvent* event, Gdk::Cursor* cursor)
 {
 	Drag::start_grab (event, cursor);
-	setup_snap_delta (_last_position.frame);
+	setup_snap_delta (_last_position);
 
 	show_verbose_cursor_time (_last_position.frame);
 
@@ -2862,7 +2879,7 @@ TrimDrag::start_grab (GdkEvent* event, Gdk::Cursor*)
 	framecnt_t const region_length = (framecnt_t) (_primary->region()->length() / speed);
 
 	framepos_t const pf = adjusted_current_frame (event);
-	setup_snap_delta (region_start);
+	setup_snap_delta (MusicFrame(region_start, 0));
 
 	if (Keyboard::modifier_state_equals (event->button.state, ArdourKeyboard::trim_contents_modifier ())) {
 		/* Move the contents of the region around without changing the region bounds */
@@ -3641,7 +3658,7 @@ void
 CursorDrag::start_grab (GdkEvent* event, Gdk::Cursor* c)
 {
 	Drag::start_grab (event, c);
-	setup_snap_delta (_editor->playhead_cursor->current_frame());
+	setup_snap_delta (MusicFrame (_editor->playhead_cursor->current_frame(), 0));
 
 	_grab_zoom = _editor->samples_per_pixel;
 
@@ -3744,7 +3761,7 @@ FadeInDrag::start_grab (GdkEvent* event, Gdk::Cursor* cursor)
 
 	AudioRegionView* arv = dynamic_cast<AudioRegionView*> (_primary);
 	boost::shared_ptr<AudioRegion> const r = arv->audio_region ();
-	setup_snap_delta (r->position());
+	setup_snap_delta (MusicFrame (r->position(), 0));
 
 	show_verbose_cursor_duration (r->position(), r->position() + r->fade_in()->back()->when, 32);
 }
@@ -3870,7 +3887,7 @@ FadeOutDrag::start_grab (GdkEvent* event, Gdk::Cursor* cursor)
 
 	AudioRegionView* arv = dynamic_cast<AudioRegionView*> (_primary);
 	boost::shared_ptr<AudioRegion> r = arv->audio_region ();
-	setup_snap_delta (r->last_frame());
+	setup_snap_delta (MusicFrame (r->last_frame(), 0));
 
 	show_verbose_cursor_duration (r->last_frame() - r->fade_out()->back()->when, r->last_frame());
 }
@@ -4031,7 +4048,7 @@ MarkerDrag::start_grab (GdkEvent* event, Gdk::Cursor* cursor)
 	} else {
 		show_verbose_cursor_time (location->end());
 	}
-	setup_snap_delta (is_start ? location->start() : location->end());
+	setup_snap_delta (MusicFrame (is_start ? location->start() : location->end(), 0));
 
 	Selection::Operation op = ArdourKeyboard::selection_type (event->button.state);
 
@@ -4418,7 +4435,7 @@ ControlPointDrag::start_grab (GdkEvent* event, Gdk::Cursor* /*cursor*/)
 	_fixed_grab_x = _point->get_x() + _editor->sample_to_pixel_unrounded (_point->line().offset());
 	_fixed_grab_y = _point->get_y();
 
-	setup_snap_delta (_editor->pixel_to_sample (_fixed_grab_x));
+	setup_snap_delta (MusicFrame (_editor->pixel_to_sample (_fixed_grab_x), 0));
 
 	float const fraction = 1 - (_point->get_y() / _point->line().height());
 	show_verbose_cursor_text (_point->line().get_verbose_cursor_string (fraction));
@@ -4916,10 +4933,10 @@ TimeFXDrag::start_grab (GdkEvent* event, Gdk::Cursor* cursor)
 
 	_editor->get_selection().add (_primary);
 
-	framepos_t where = _primary->region()->position();
+	MusicFrame where (_primary->region()->position(), 0);
 	setup_snap_delta (where);
 
-	show_verbose_cursor_duration (where, adjusted_current_frame (event), 0);
+	show_verbose_cursor_duration (where.frame, adjusted_current_frame (event), 0);
 }
 
 void
@@ -5627,6 +5644,7 @@ NoteDrag::NoteDrag (Editor* e, ArdourCanvas::Item* i)
 	: Drag (e, i)
 	, _cumulative_dx (0)
 	, _cumulative_dy (0)
+	, _earliest (0.0)
 	, _was_selected (false)
 	, _copy (false)
 {
@@ -5639,6 +5657,13 @@ NoteDrag::NoteDrag (Editor* e, ArdourCanvas::Item* i)
 }
 
 void
+NoteDrag::setup_pointer_frame_offset ()
+{
+	_pointer_frame_offset = raw_grab_frame()
+		- _editor->session()->tempo_map().frame_at_quarter_note (_region->session_relative_qn (_primary->note()->time().to_double()));
+}
+
+void
 NoteDrag::start_grab (GdkEvent* event, Gdk::Cursor *)
 {
 	Drag::start_grab (event);
@@ -5649,7 +5674,7 @@ NoteDrag::start_grab (GdkEvent* event, Gdk::Cursor *)
 		_copy = false;
 	}
 
-	setup_snap_delta (_region->source_beats_to_absolute_frames (_primary->note()->time ()));
+	setup_snap_delta (MusicFrame (_region->source_beats_to_absolute_frames (_primary->note()->time ()), 0));
 
 	if (!(_was_selected = _primary->selected())) {
 
@@ -5673,55 +5698,38 @@ NoteDrag::start_grab (GdkEvent* event, Gdk::Cursor *)
 	}
 }
 
-/** @return Current total drag x change in frames */
-frameoffset_t
-NoteDrag::total_dx (const guint state) const
+/** @return Current total drag x change in quarter notes */
+double
+NoteDrag::total_dx (GdkEvent * event) const
 {
 	if (_x_constrained) {
 		return 0;
 	}
+
 	TempoMap& map (_editor->session()->tempo_map());
 
 	/* dx in frames */
 	frameoffset_t const dx = _editor->pixel_to_sample (_drags->current_pointer_x() - grab_x());
 
 	/* primary note time */
-	double const quarter_note_start = _region->region()->quarter_note() - _region->midi_region()->start_beats();
-	frameoffset_t const n = map.frame_at_quarter_note (quarter_note_start + _primary->note()->time().to_double());
-
-	/* new time of the primary note in session frames */
-	frameoffset_t st = n + dx + snap_delta (state);
-
-	framepos_t const rp = _region->region()->position ();
+	frameoffset_t const n = map.frame_at_quarter_note (_region->session_relative_qn (_primary->note()->time().to_double()));
 
-	/* prevent the note being dragged earlier than the region's position */
-	st = max (st, rp);
+	/* primary note time in quarter notes */
+	double const n_qn = _region->session_relative_qn (_primary->note()->time().to_double());
 
-	/* possibly snap and return corresponding delta */
+	/* new time of the primary note in session frames */
+	frameoffset_t st = n + dx + snap_delta (event->button.state);
 
-	bool snap = true;
+	/* possibly snap and return corresponding delta in quarter notes */
+	MusicFrame snap (st, 0);
+	_editor->snap_to_with_modifier (snap, event);
+	double ret = map.exact_qn_at_frame (snap.frame, snap.division) - n_qn - snap_delta_music (event->button.state);
 
-	if (ArdourKeyboard::indicates_snap (state)) {
-		if (_editor->snap_mode () != SnapOff) {
-			snap = false;
-		}
-	} else {
-		if (_editor->snap_mode () == SnapOff) {
-			snap = false;
-			/* inverted logic here - we;re in snapoff but we've pressed the snap delta modifier */
-			if (ArdourKeyboard::indicates_snap_delta (state)) {
-				snap = true;
-			}
-		}
+	/* prevent the earliest note being dragged earlier than the region's start position */
+	if (_earliest + ret < _region->midi_region()->start_beats()) {
+		ret -= (_earliest + ret) - _region->midi_region()->start_beats();
 	}
 
-	frameoffset_t ret;
-	if (snap) {
-		bool const ensure_snap = _editor->snap_mode () != SnapMagnetic;
-		ret =  _region->snap_frame_to_frame (st - rp, ensure_snap) + rp - n - snap_delta (state);
-	} else {
-		ret = st - n - snap_delta (state);
-	}
 	return ret;
 }
 
@@ -5747,30 +5755,33 @@ NoteDrag::total_dy () const
 void
 NoteDrag::motion (GdkEvent * event, bool first_move)
 {
-	if (_copy && first_move) {
-		/* make copies of all the selected notes */
-		_primary = _region->copy_selection ();
+	if (first_move) {
+		_earliest = _region->earliest_in_selection().to_double();
+		if (_copy) {
+			/* make copies of all the selected notes */
+			_primary = _region->copy_selection (_primary);
+		}
 	}
 
 	/* Total change in x and y since the start of the drag */
-	frameoffset_t const dx = total_dx (event->button.state);
+	double const dx_qn = total_dx (event);
 	int8_t const dy = total_dy ();
 
 	/* Now work out what we have to do to the note canvas items to set this new drag delta */
-	double const tdx = _x_constrained ? 0 : _editor->sample_to_pixel (dx) - _cumulative_dx;
+	double const tdx = _x_constrained ? 0 : dx_qn - _cumulative_dx;
 	double const tdy = _y_constrained ? 0 : -dy * _note_height - _cumulative_dy;
 
 	if (tdx || tdy) {
-		_cumulative_dx += tdx;
+		_cumulative_dx = dx_qn;
 		_cumulative_dy += tdy;
 
 		int8_t note_delta = total_dy();
 
 		if (tdx || tdy) {
 			if (_copy) {
-				_region->move_copies (tdx, tdy, note_delta);
+				_region->move_copies (dx_qn, tdy, note_delta);
 			} else {
-				_region->move_selection (tdx, tdy, note_delta);
+				_region->move_selection (dx_qn, tdy, note_delta);
 			}
 
 			/* the new note value may be the same as the old one, but we
@@ -5831,7 +5842,7 @@ NoteDrag::finished (GdkEvent* ev, bool moved)
 			}
 		}
 	} else {
-		_region->note_dropped (_primary, total_dx (ev->button.state), total_dy(), _copy);
+		_region->note_dropped (_primary, total_dx (ev), total_dy(), _copy);
 	}
 }
 
diff --git a/gtk2_ardour/editor_drag.h b/gtk2_ardour/editor_drag.h
index 95eaf1409b..711b5095c7 100644
--- a/gtk2_ardour/editor_drag.h
+++ b/gtk2_ardour/editor_drag.h
@@ -242,12 +242,13 @@ protected:
 	}
 
 	ARDOUR::frameoffset_t snap_delta (guint const) const;
+	double  snap_delta_music (guint const) const;
 
 	double current_pointer_x () const;
 	double current_pointer_y () const;
 
 	/* sets snap delta from unsnapped pos */
-	void setup_snap_delta (framepos_t pos);
+	void setup_snap_delta (ARDOUR::MusicFrame pos);
 
 	boost::shared_ptr<ARDOUR::Region> add_midi_region (MidiTimeAxisView*, bool commit);
 
@@ -282,6 +283,7 @@ private:
 	 *  framepos. used for relative snap.
 	 */
 	framepos_t _snap_delta;
+	double     _snap_delta_music;
 	CursorContext::Handle _cursor_ctx; ///< cursor change context
 	bool _constraint_pressed; ///< if the keyboard indicated constraint modifier was pressed on start_grab()
 };
@@ -557,15 +559,17 @@ class NoteDrag : public Drag
 	void finished (GdkEvent *, bool);
 	void aborted (bool);
 
+	void setup_pointer_frame_offset ();
   private:
 
-	ARDOUR::frameoffset_t total_dx (const guint) const;
+	double total_dx (GdkEvent * event) const; // total movement in quarter notes
 	int8_t total_dy () const;
 
 	MidiRegionView* _region;
 	NoteBase* _primary;
 	double _cumulative_dx;
 	double _cumulative_dy;
+	double _earliest; // earliest quarter note in note selection
 	bool   _was_selected;
 	double _note_height;
 	bool   _copy;
diff --git a/gtk2_ardour/midi_region_view.cc b/gtk2_ardour/midi_region_view.cc
index da7f1a54b5..f9c088448e 100644
--- a/gtk2_ardour/midi_region_view.cc
+++ b/gtk2_ardour/midi_region_view.cc
@@ -2549,11 +2549,9 @@ MidiRegionView::add_to_selection (NoteBase* ev)
 	}
 }
 
-void
-MidiRegionView::move_selection(double dx, double dy, double cumulative_dy)
+Evoral::Beats
+MidiRegionView::earliest_in_selection ()
 {
-	typedef vector<boost::shared_ptr<NoteType> > PossibleChord;
-	PossibleChord to_play;
 	Evoral::Beats earliest = Evoral::MaxBeats;
 
 	for (Selection::iterator i = _selection.begin(); i != _selection.end(); ++i) {
@@ -2562,10 +2560,27 @@ MidiRegionView::move_selection(double dx, double dy, double cumulative_dy)
 		}
 	}
 
+	return earliest;
+}
+
+void
+MidiRegionView::move_selection(double dx_qn, double dy, double cumulative_dy)
+{
+	typedef vector<boost::shared_ptr<NoteType> > PossibleChord;
+	Editor* editor = dynamic_cast<Editor*> (&trackview.editor());
+	TempoMap& tmap (editor->session()->tempo_map());
+	PossibleChord to_play;
+	Evoral::Beats earliest = earliest_in_selection();
+
 	for (Selection::iterator i = _selection.begin(); i != _selection.end(); ++i) {
-		if ((*i)->note()->time() == earliest) {
-			to_play.push_back ((*i)->note());
+		NoteBase* n = *i;
+		if (n->note()->time() == earliest) {
+			to_play.push_back (n->note());
 		}
+		double const note_time_qn = session_relative_qn (n->note()->time().to_double());
+		double const dx = editor->sample_to_pixel_unrounded (tmap.frame_at_quarter_note (note_time_qn + dx_qn))
+			- n->item()->item_to_canvas (ArdourCanvas::Duple (n->x0(), 0)).x;
+
 		(*i)->move_event(dx, dy);
 	}
 
@@ -2593,15 +2608,17 @@ MidiRegionView::move_selection(double dx, double dy, double cumulative_dy)
 }
 
 NoteBase*
-MidiRegionView::copy_selection ()
+MidiRegionView::copy_selection (NoteBase* primary)
 {
-	NoteBase* note;
 	_copy_drag_events.clear ();
 
 	if (_selection.empty()) {
 		return 0;
 	}
 
+	NoteBase* note;
+	NoteBase* ret = 0;
+
 	for (Selection::iterator i = _selection.begin(); i != _selection.end(); ++i) {
 		boost::shared_ptr<NoteType> g (new NoteType (*((*i)->note())));
 		if (midi_view()->note_mode() == Sustained) {
@@ -2614,29 +2631,34 @@ MidiRegionView::copy_selection ()
 			note = h;
 		}
 
+		if ((*i) == primary) {
+			ret = note;
+		}
+
 		_copy_drag_events.push_back (note);
 	}
 
-	return _copy_drag_events.front ();
+	return ret;
 }
 
 void
-MidiRegionView::move_copies (double dx, double dy, double cumulative_dy)
+MidiRegionView::move_copies (double dx_qn, double dy, double cumulative_dy)
 {
 	typedef vector<boost::shared_ptr<NoteType> > PossibleChord;
+	Editor* editor = dynamic_cast<Editor*> (&trackview.editor());
+	TempoMap& tmap (editor->session()->tempo_map());
 	PossibleChord to_play;
-	Evoral::Beats earliest = Evoral::MaxBeats;
+	Evoral::Beats earliest = earliest_in_selection();
 
 	for (CopyDragEvents::iterator i = _copy_drag_events.begin(); i != _copy_drag_events.end(); ++i) {
-		if ((*i)->note()->time() < earliest) {
-			earliest = (*i)->note()->time();
+		NoteBase* n = *i;
+		if (n->note()->time() == earliest) {
+			to_play.push_back (n->note());
 		}
-	}
+		double const note_time_qn = session_relative_qn (n->note()->time().to_double());
+		double const dx = editor->sample_to_pixel_unrounded (tmap.frame_at_quarter_note (note_time_qn + dx_qn))
+			- n->item()->item_to_canvas (ArdourCanvas::Duple (n->x0(), 0)).x;
 
-	for (CopyDragEvents::iterator i = _copy_drag_events.begin(); i != _copy_drag_events.end(); ++i) {
-		if ((*i)->note()->time() == earliest) {
-			to_play.push_back ((*i)->note());
-		}
 		(*i)->move_event(dx, dy);
 	}
 
@@ -2664,7 +2686,7 @@ MidiRegionView::move_copies (double dx, double dy, double cumulative_dy)
 }
 
 void
-MidiRegionView::note_dropped(NoteBase *, frameoffset_t dt, int8_t dnote, bool copy)
+MidiRegionView::note_dropped(NoteBase *, double d_qn, int8_t dnote, bool copy)
 {
 	uint8_t lowest_note_in_selection  = 127;
 	uint8_t highest_note_in_selection = 0;
@@ -2693,15 +2715,13 @@ MidiRegionView::note_dropped(NoteBase *, frameoffset_t dt, int8_t dnote, bool co
 		if (highest_note_in_selection + dnote > 127) {
 			highest_note_difference = highest_note_in_selection - 127;
 		}
-		TempoMap& map (trackview.session()->tempo_map());
 
 		start_note_diff_command (_("move notes"));
 
 		for (Selection::iterator i = _selection.begin(); i != _selection.end() ; ++i) {
 
-			double const start_qn = _region->quarter_note() - midi_region()->start_beats();
-			framepos_t new_frames = map.frame_at_quarter_note (start_qn + (*i)->note()->time().to_double()) + dt;
-			Evoral::Beats new_time = Evoral::Beats (map.quarter_note_at_frame (new_frames) - start_qn);
+			Evoral::Beats new_time = Evoral::Beats (max ((*i)->note()->time().to_double() + d_qn, midi_region()->start_beats()));
+
 			if (new_time < 0) {
 				continue;
 			}
@@ -2734,16 +2754,12 @@ MidiRegionView::note_dropped(NoteBase *, frameoffset_t dt, int8_t dnote, bool co
 			highest_note_difference = highest_note_in_selection - 127;
 		}
 
-		TempoMap& map (trackview.session()->tempo_map());
 		start_note_diff_command (_("copy notes"));
 
 		for (CopyDragEvents::iterator i = _copy_drag_events.begin(); i != _copy_drag_events.end() ; ++i) {
 
 			/* update time */
-
-			double const start_qn = _region->quarter_note() - midi_region()->start_beats();
-			framepos_t new_frames = map.frame_at_quarter_note (start_qn + (*i)->note()->time().to_double()) + dt;
-			Evoral::Beats new_time = Evoral::Beats (map.quarter_note_at_frame (new_frames) - start_qn);
+			Evoral::Beats new_time = Evoral::Beats (max ((*i)->note()->time().to_double() + d_qn, midi_region()->start_beats()));
 
 			if (new_time < 0) {
 				continue;
@@ -2790,7 +2806,7 @@ framepos_t
 MidiRegionView::snap_pixel_to_sample(double x, bool ensure_snap)
 {
 	PublicEditor& editor (trackview.editor());
-	return snap_frame_to_frame (editor.pixel_to_sample (x), ensure_snap);
+	return snap_frame_to_frame (editor.pixel_to_sample (x), ensure_snap).frame;
 }
 
 /** @param x Pixel relative to the region position.
@@ -4369,3 +4385,9 @@ MidiRegionView::note_to_y(uint8_t note) const
 {
 	return contents_height() - (note + 1 - _current_range_min) * note_height() + 1;
 }
+
+double
+MidiRegionView::session_relative_qn (double qn) const
+{
+	return qn + (region()->quarter_note() - midi_region()->start_beats());
+}
diff --git a/gtk2_ardour/midi_region_view.h b/gtk2_ardour/midi_region_view.h
index 929b3bd7f9..0d5b82255d 100644
--- a/gtk2_ardour/midi_region_view.h
+++ b/gtk2_ardour/midi_region_view.h
@@ -200,10 +200,11 @@ public:
 	void   select_range(framepos_t start, framepos_t end);
 	void   invert_selection ();
 
+	Evoral::Beats earliest_in_selection ();
 	void move_selection(double dx, double dy, double cumulative_dy);
-	void note_dropped (NoteBase* ev, ARDOUR::frameoffset_t, int8_t d_note, bool copy);
-	NoteBase* copy_selection ();
-	void move_copies(double dx, double dy, double cumulative_dy);
+	void note_dropped (NoteBase* ev, double d_qn, int8_t d_note, bool copy);
+	NoteBase* copy_selection (NoteBase* primary);
+	void move_copies(double dx_qn, double dy, double cumulative_dy);
 
 	void select_notes (std::list<Evoral::event_id_t>);
 	void select_matching_notes (uint8_t notenum, uint16_t channel_mask, bool add, bool extend);
@@ -297,6 +298,8 @@ public:
 		return _region_relative_time_converter_double;
 	}
 
+	double session_relative_qn (double qn) const;
+
 	void goto_previous_note (bool add_to_selection);
 	void goto_next_note (bool add_to_selection);
 	void change_note_lengths (bool, bool, Evoral::Beats beats, bool start, bool end);
diff --git a/gtk2_ardour/region_view.cc b/gtk2_ardour/region_view.cc
index 9f6ff645ce..c689a15e7d 100644
--- a/gtk2_ardour/region_view.cc
+++ b/gtk2_ardour/region_view.cc
@@ -943,7 +943,7 @@ RegionView::move_contents (frameoffset_t distance)
  *  Used when inverting snap mode logic with key modifiers, or snap distance calculation.
  *  @return Snapped frame offset from this region's position.
  */
-frameoffset_t
+MusicFrame
 RegionView::snap_frame_to_frame (frameoffset_t x, bool ensure_snap) const
 {
 	PublicEditor& editor = trackview.editor();
@@ -960,6 +960,6 @@ RegionView::snap_frame_to_frame (frameoffset_t x, bool ensure_snap) const
 		editor.snap_to (frame, RoundUpAlways, false, ensure_snap);
 	}
 
-	/* back to region relative */
-	return frame.frame - _region->position();
+	/* back to region relative, keeping the relevant divisor */
+	return MusicFrame (frame.frame - _region->position(), frame.division);
 }
diff --git a/gtk2_ardour/region_view.h b/gtk2_ardour/region_view.h
index 7fad731dc2..10eb7b5dc6 100644
--- a/gtk2_ardour/region_view.h
+++ b/gtk2_ardour/region_view.h
@@ -121,7 +121,7 @@ class RegionView : public TimeAxisViewItem
 		}
 	};
 
-	ARDOUR::frameoffset_t snap_frame_to_frame (ARDOUR::frameoffset_t, bool ensure_snap = false) const;
+	ARDOUR::MusicFrame snap_frame_to_frame (ARDOUR::frameoffset_t, bool ensure_snap = false) const;
 
   protected: